Such an apparatus and such a method are known from DE 100 07 711 C1. There, a laser sintering apparatus is described wherein the temperature of the sinter powder in a moving detection area in the region of the sintering position is detected by means of a pyrometer and wherein the power of the laser is regulated in relation to the temperature detected.
Therein, the thermal radiation of the sintering position has a considerable influence on the temperature measured by the pyrometer. Depending on the degree of exposure of the powder, the emission capability of the surface is changing (ratio of the radiation energy emitted by the surface to the radiation energy emitted by a black body at the same temperature), thus falsifying the measurement result. Furthermore, the temperature measurement is falsified by reflected laser radiation. For that reason, the temperature thus measured does not represent a good measure for the temperature of the surface of the powder. bed. In laser sintering, however, the temperature of the powder bed surface is a decisive parameter for the quality of the produced component in relation to the building material used (sinter powder).
EP 1 466 718 A2 and EP 1 296 788 B1 each disclose an apparatus for the manufacture of a three-dimensional object, wherein the temperature of the powder bed surface over the entire working area is simultaneously measured by means of an IR camera in a spatially-resolved manner. One problem is that the optical system of the IR camera might become dirty in the apparatus. This dirt, which cannot be avoided entirely by blowing, results in measurement results which may be falsified in a position-depending manner. Furthermore, this temperature measurement is to disadvantage in that the IR camera is very expensive as compared with other non-contact temperature measuring instruments, such as a pyrometer.
For that reason, the present invention aims at providing an easy-to-handle and cost-effective apparatus and a simple and cost-effective method for the manufacture of a three-dimensional object by solidifying layers of a building material at the positions corresponding to the particular cross-section of the object, through the action of electromagnetic radiation or particle radiation, wherein said apparatus and said method can be used to produce three-dimensional objects of a high quality.